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commit 8b0059ccd744c43b9119a2bd31b581e8a55d0cdf Author: Alex Herbert <[email protected]> AuthorDate: Fri Aug 13 19:40:25 2021 +0100 Use java.util.function.DoubleUnaryOperator Return lambdas. --- .../rng/sampling/shape/UnitBallSamplerTest.java | 110 +++------------------ 1 file changed, 16 insertions(+), 94 deletions(-) diff --git a/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/shape/UnitBallSamplerTest.java b/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/shape/UnitBallSamplerTest.java index 5a030c8..72b400b 100644 --- a/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/shape/UnitBallSamplerTest.java +++ b/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/shape/UnitBallSamplerTest.java @@ -17,7 +17,7 @@ package org.apache.commons.rng.sampling.shape; import java.util.Arrays; - +import java.util.function.DoubleUnaryOperator; import org.junit.Assert; import org.junit.Test; @@ -110,11 +110,11 @@ public class UnitBallSamplerTest { final int orthants = 1 << dimension; // Compute the radius for each layer to have the same volume. - final double volume = createVolumeFunction(dimension).apply(1); + final double volume = createVolumeFunction(dimension).applyAsDouble(1); final DoubleUnaryOperator radius = createRadiusFunction(dimension); final double[] r = new double[layers]; for (int i = 1; i < layers; i++) { - r[i - 1] = radius.apply(volume * ((double) i / layers)); + r[i - 1] = radius.applyAsDouble(volume * ((double) i / layers)); } // The final radius should be 1.0. Any coordinates with a radius above 1 // should fail so explicitly set the value as 1. @@ -273,28 +273,12 @@ public class UnitBallSamplerTest { final DoubleUnaryOperator volume = createVolumeFunction(n); final DoubleUnaryOperator radius = createRadiusFunction(n); for (final double r : radii) { - Assert.assertEquals(r, radius.apply(volume.apply(r)), 1e-10); + Assert.assertEquals(r, radius.applyAsDouble(volume.applyAsDouble(r)), 1e-10); } } } /** - * Specify computation of a double-valued result for a given double. - * - * <p>This can be replaced with java.util.function.DoubleUnaryOperator when the source - * requires Java 1.8. - */ - private interface DoubleUnaryOperator { - /** - * Compute the result. - * - * @param value the input value - * @return the result - */ - double apply(double value); - } - - /** * Creates a function to compute the volume of a ball of the given dimension * from the radius. * @@ -303,53 +287,22 @@ public class UnitBallSamplerTest { * @see <a href="https://en.wikipedia.org/wiki/Volume_of_an_n-ball";>Volume of an n-ball</a> */ private static DoubleUnaryOperator createVolumeFunction(final int dimension) { - // This can be simplified using lambda functions when the source requires Java 1.8 if (dimension == 1) { - return new DoubleUnaryOperator() { - @Override - public double apply(double r) { - return r * 2; - } - }; + return r -> r * 2; } else if (dimension == 2) { - return new DoubleUnaryOperator() { - @Override - public double apply(double r) { - return Math.PI * r * r; - } - }; + return r -> Math.PI * r * r; } else if (dimension == 3) { final double factor = 4 * Math.PI / 3; - return new DoubleUnaryOperator() { - @Override - public double apply(double r) { - return factor * Math.pow(r, 3); - } - }; + return r -> factor * Math.pow(r, 3); } else if (dimension == 4) { final double factor = Math.PI * Math.PI / 2; - return new DoubleUnaryOperator() { - @Override - public double apply(double r) { - return factor * Math.pow(r, 4); - } - }; + return r -> factor * Math.pow(r, 4); } else if (dimension == 5) { final double factor = 8 * Math.PI * Math.PI / 15; - return new DoubleUnaryOperator() { - @Override - public double apply(double r) { - return factor * Math.pow(r, 5); - } - }; + return r -> factor * Math.pow(r, 5); } else if (dimension == 6) { final double factor = Math.pow(Math.PI, 3) / 6; - return new DoubleUnaryOperator() { - @Override - public double apply(double r) { - return factor * Math.pow(r, 6); - } - }; + return r -> factor * Math.pow(r, 6); } throw new IllegalStateException("Unsupported dimension: " + dimension); } @@ -363,53 +316,22 @@ public class UnitBallSamplerTest { * @see <a href="https://en.wikipedia.org/wiki/Volume_of_an_n-ball";>Volume of an n-ball</a> */ private static DoubleUnaryOperator createRadiusFunction(final int dimension) { - // This can be simplified using lambda functions when the source requires Java 1.8 if (dimension == 1) { - return new DoubleUnaryOperator() { - @Override - public double apply(double v) { - return v * 0.5; - } - }; + return v -> v * 0.5; } else if (dimension == 2) { - return new DoubleUnaryOperator() { - @Override - public double apply(double v) { - return Math.sqrt(v / Math.PI); - } - }; + return v -> Math.sqrt(v / Math.PI); } else if (dimension == 3) { final double factor = 3.0 / (4 * Math.PI); - return new DoubleUnaryOperator() { - @Override - public double apply(double v) { - return Math.cbrt(v * factor); - } - }; + return v -> Math.cbrt(v * factor); } else if (dimension == 4) { final double factor = 2.0 / (Math.PI * Math.PI); - return new DoubleUnaryOperator() { - @Override - public double apply(double v) { - return Math.pow(v * factor, 0.25); - } - }; + return v -> Math.pow(v * factor, 0.25); } else if (dimension == 5) { final double factor = 15.0 / (8 * Math.PI * Math.PI); - return new DoubleUnaryOperator() { - @Override - public double apply(double v) { - return Math.pow(v * factor, 0.2); - } - }; + return v -> Math.pow(v * factor, 0.2); } else if (dimension == 6) { final double factor = 6.0 / Math.pow(Math.PI, 3); - return new DoubleUnaryOperator() { - @Override - public double apply(double v) { - return Math.pow(v * factor, 1.0 / 6); - } - }; + return v -> Math.pow(v * factor, 1.0 / 6); } throw new IllegalStateException("Unsupported dimension: " + dimension); }
